In the field of food processing, it is common to process food at one location and transport bulk quantities to another location for further processing or final packaging. Various methods have been developed for containing and transporting food products. For example, fruit juice or milk is often processed at one facility and sent to another facility for final packaging. The two facilities may be located in close proximity to each other or may be in different countries. Because food products are susceptible to degradation due to microbial spoilage, various processing methods are used to retard or prevent the growth of microorganisms during this transportation and storage. These include sterilizing the food product inside a container, hot-filling a clean container, or putting the sterile food product into a sterile container. Other methods include freezing, refrigeration or the use of preservatives.
Disadvantages of sterilizing inside a container include the expense of such a container and the food product degradation due to the amount of heat required. Also, because of the need to sterilize the cold point of the food product, this type of processing is common for final packaging, but not typically done for bulk products. Bulk food product is food product in a quantity that is much larger than that in the final retail or food service package. Bulk food product is typically more than 50 gallons, for example. Likewise, hot filling is typically used for final packaging, but not for bulk products.
In contrast, freezing is a typical method for processing bulk products for transportation. For example, pasteurized fruit juices are often filled into 55 gallon drums, often with a drum liner, and then frozen prior to shipping. Disadvantages of freezing include the energy required for freezing, the energy required to keep the product frozen during the transportation and storage cycle, and the cost of the drums. Additional disadvantages include the potential physical and chemical changes of the product due to freezing. For example, when citrus pulp cells are frozen, the cell walls are disrupted. Upon thawing, the pulp cells have different physical characteristics than pulp cells that have not been frozen.
There are many disadvantages to the use of chemical preservatives for certain food products. These include consumer perception and changes in flavor. In many food products, the use of preservatives is not allowed under standard of identity or by law.
For certain food products, the method of putting a sterile food product into a sterile container has many advantages over the above mentioned processes. This method is typically referred to as aseptic processing. In aseptic processing, a food product is pasteurized to a point where it is considered commercially sterile. In such a state, there is a very low probability of the presence or growth of microorganisms. The sterilized food product is then placed into a sterile container in such as way as to avoid the introduction of microorganisms. Aseptic processing can be used to put sterilized food product into the final consumer container (for example, shelf stable milk or juice) or can be used to store and transport bulk food products in an aseptic state. For example, juices and tomato products are often pasteurized and aseptically filled into 300 gallon bags for storage and transportation to other food processing facilities. Likewise, juices may be pasteurized and aseptically filled into large permanent bulk containers (currently up to two million gallons) for storage prior to blending and packaging.
The most common form of aseptic food product transportation includes the use of 300 gallon bags as mentioned above. Such a bag is filled within a disposable or re-usable container such as a wooden box, or re-usable plastic container, and the bag is sealed with a cap after filling. The wooden or plastic container supports the bag and allows for the boxes to be stacked during transportation. Citrus pulp is currently aseptically filled into such “bag-in-the-box” containers. While widely used, the disadvantages of this method include the cost of the bags and the boxes. When shipped overseas, the return of empty boxes for further use incurs additional cost. An additional disadvantage of such a system is that the bags cannot be aseptically unloaded. At the point of use, the bags are cut open and the product is dumped or pumped out of the bags. It is therefore necessary to further pasteurize the product prior to final packaging.
Another method of aseptic transportation involves the use of aseptic tankers or rail cars and over-the-road containers. The rail cars typically had cone shaped hoppers on the bottom. This method was used by Bishopric Products Co. (formerly of Cincinnati, Ohio) to transport tomato product (Food Technology, July 1976). Tankers were sterilized through the use of steam or chemical sterilant (iodophor, for example) and then filled with sterile product. Such food product was kept under pressure with sterile gas during transportation and was successfully transported in an aseptic state from one site to another.
For example, U.S. Pat. No. 3,209,675 discloses an apparatus for the aseptic transportation of perishable liquids. The apparatus described is a transportable container, sterilized by a chemical sterilant (peracetic acid) and kept pressurized during transportation by the use of a cylinder of inert gas. U.S. Pat. Nos. 6,030,580 and 6,277,328 also disclose a method of aseptically transporting bulk food product in a transportable container. The use of aseptic tankers or rail cars as described in these patents overcomes the cost of bags and boxes and provides for a more economical method of transporting aseptic product.
Hawaii Intermodal Tank Transport LLC, of Palmetto, Fla., supplies aseptic intermodal containers for the aseptic transportation of food product. Such intermodal containers use the same principles as mentioned above for aseptic tankers and rail cars, but provide the additional advantage of being configurable to be transportable by truck, rail or ship. Juice is currently being aseptically transported in such intermodal containers.
With reference to FIG. 1, such an intermodal container 30 includes a cylindrically shaped rigid shell 31 that may be approximately 20 feet long, and that may hold approximately 24,000 liters. The shell includes rear and front closed ends 32a, 32b in the form of shallow domes. A discharge port is positioned behind a rear panel access door 33 at the bottom of the rear closed end 32a. The intermodal container 30 also includes a pair of rear and front rectangular support frame assemblies 35a, 35b that support the rigid shell and permit stacking of the containers, such as for transportation via ship, or when in a storage area, for example. The container 30 may also include inwardly extending corner support arms, not shown, that extend inwardly from the corners of the respective support frame assemblies 35a, 35b and attach to the rigid shell 31. The intermodal container 30 also illustratively includes a ladder 36 carried by the rear support frame assembly 35a, and a horizontal walking platform 37 to facilitate access to the manway and other ports on the top of the rigid shell 31. The intermodal container 30 in some configurations may include an insulation layer associated with the rigid shell 31. In addition, a portable refrigeration unit may be provided to keep the contents cold, and one or more temperature and/or pressure sensors may be provided to monitor the contents.
While providing a safe and economical method to aseptically transport liquid food products, the use of aseptic tankers, rail cars and intermodal containers does not lend itself to the aseptic transportation of high viscosity products, such as, for example, tomato paste, high viscosity fruit purees or citrus pulp. High viscosity food products may be considered as food products that do not readily flow by gravity. These products, if placed into a typical tank with a free-draining bottom will not flow out of the tank or will flow at such a slow speed that gravity draining is impractical. Such products may be pumpable with the correct pump selection and can thus be pumped into an aseptic container. However, because these products do not readily flow by gravity, it is not easy to remove such high viscosity food products from such a container.
An intermodal container typically also includes an aseptic filling/discharge valve that is used to both fill and discharge the food product. When switching from one container to another, a hose is disconnected from one container and connected to another. Since the hose is disconnected and exposed to the atmosphere, the aseptic condition is lost. Therefore, the hose is re-sterilized when connected to the next container. In addition, an outer chamber of the filling valve is also sterilized before passing sterile food product through the valve. This sterilization process may require a substantial amount of time between containers. Since it is a manually intensive process, it may be susceptible to user-error which could result in product contamination. Such aseptic filling of tanks and containers is disclosed, for example, in U.S. Pat. Nos. 3,951,184 and 4,047,547, the entire disclosures of which are incorporated herein by reference in their entireties.
U.S. Pat. No. 3,209,675, for example, discloses an apparatus for the aseptic transportation of perishable liquids. The apparatus described is a transportable container, sterilized by a chemical sterilant (peracetic acid) and kept pressurized during transportation by use of a cylinder of inert gas. U.S. Pat. Nos. 6,030,580 and 6,277,328 both describe the aseptic transportation of food product with a chemical sterilant.
Juice and other liquid food products are currently being aseptically transported in intermodal containers by Hawaii Intermodal Tank Transport. The intermodal containers can be transported by truck, rail or ship, and they are filled and discharged through a single valve located on the low point of the tank. Re-sterilization of the filling line is required between each container.